public class Example3_7 {
    public static void main(String args[]) {
       double sum = 0,item = 1;
       int i = 1,n = 20;
       while(i<=n) {
          sum = sum+item;
          i = i+1;
          item = item*(1.0/i);
       }
       System.out.println("sum="+sum);
   }

}

        
